The present invention relates generally to forming a sealed air gap in semiconductor chips. In particular, the present invention provides a semiconductor chip and method for forming sealed air gaps in semiconductor chips by removing sacrificial spacers adjacent to gates after contact formation.
Semiconductor chips continue to be used in an increasing variety of electronic devices. Simultaneously, the trend in semiconductor chips is to create greater functional capacity with smaller devices. As a result, forming more efficient semiconductor chips requires that the components of semiconductor chips operate more efficiently.
Spacers including silicon nitride formed adjacent to gate sidewalls have a relatively high dielectric constant resulting in gate-to-diffusion and gate-to-contact parasitic capacitances that increase power consumption and reduce performance of semiconductor chips. Spacers including oxide have lower parasitic capacitance but do not stand up well to middle-of-line (MOL) processing. Replacing nitride spacers with oxide results in a lower parasitic capacitance.
Air gaps formed adjacent to gate sidewalls provide the lowest possible dielectric constant with the lowest parasitic capacitance.